Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
su sach » so sach
vu sach » vu bach, vu khach
hieu le » hieu ve, hieu he, hieu ly
thu vat » thuc vat, thu va, thuat vat
hanh di » hanh vi, hanh de, hang di
cua tre » cuu tre, cua triet, dua tren
y nang » ky nang, ly nang, v nang
le nam » ly nam, he nam, le na
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu sach)) y nang x hoi. hieu le nam thu vat hanh di ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y nang x hoi. hieu le nam thu vat hanh di ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) y nang x hoi. hieu le nam thu vat hanh di ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) y nang x hoi. hieu le nam thu vat hanh di ((cua tre) OR (cua te))*.